9213
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12768
- Proper Divisor Sum (Aliquot Sum)
- 3555
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5904
- Möbius Function
- -1
- Radical
- 9213
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 60
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Smallest number that requires n iterations of the bi-unitary totient function (A116550) to reach 1.at n=40A005424
- Integer part of ((4th elementary symmetric function of 1,2,..,n)/(2nd elementary symmetric function of 1,2,...,n)).at n=25A024173
- For n odd, >1, not divisible by 3, we can write 3/n = 1/a + 1/b + 1/c with a>b>c>0, a,b,c distinct and odd; sequence gives smallest a.at n=26A027442
- For n != 1 mod 3, we can write 3/(2n+1) = 1/a + 1/b + 1/c with a>b>c>0, a,b,c distinct and odd; sequence gives smallest such a, or 1 if n = 1 mod 3.at n=40A027443
- Number of matchings in graph C_{5} X P_{n}.at n=3A033517
- a(n) = (3*n - 1)*(4*n - 1).at n=28A033578
- a(n) = T(4,n), array T given by A047858.at n=10A047861
- a(n) is the smallest value of m such that A002378(m), the m-th oblong number, contains exactly n 8's.at n=4A048545
- Expansion of 1/(1-x^2-2*x^3).at n=24A052947
- Number of rooted 5-connected planar triangulations with 2n faces.at n=8A064521
- a(n) is the first of a triple of consecutive integers, each of which is the product of three distinct primes.at n=17A066509
- Let u(1)=u(2)=1, u(3)=n, u(k) = (1/2)*abs(2*u(k-1) -u(k-2)-u(k-3)); sequence gives values of n such that Sum_{k>=1} u(k) is an integer.at n=21A078113
- Expansion of (1-x)/((1-x)^2 - 4*x^3).at n=12A097117
- Number of matchings in the C_n X P_3 graph (C_n is the cycle graph on n vertices and P_3 is the path graph on 3 vertices).at n=3A102090
- Expansion of g.f. (x^2+x+1)*(2*x^2+2*x+1)*(x-1)^2/((1-x^2-2*x^3)*(x^4+1)).at n=25A107850
- Numbers n such that first occurrence of the 10 digits of the i-th root of n contain all the digits from 0 to 9.at n=8A119521
- The first 8 values are predefined, the remaining set to a(n) = 48*prime(n)+n+2.at n=42A129025
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.at n=13A146036
- Divisors of 9213.at n=7A151730
- a(n) = 9*n^2 - 3.at n=31A157872